This invention relates to a refrigerant hose.
Use of a resin-rubber laminate comprising a resin material having a low gas permeability such as polyamide and a rubber material has become popular in producing a hose used for delivering a refrigerant in automobile air conditioner and the like. When the adhesion between the resin material and the rubber material is insufficient in such a resin-rubber laminate, a gas or a liquid may become clogged at the boundary between the resin material and the rubber material, and a bulge will be formed in the resin at the site of the clogging. This problem has been usually obviated by the application of an adhesive or surface treatment on the resin material. JP 3074700 B, for example, discloses a refrigerant hose having a gas barrier layer and a rubber layer comprising a particular rubber composition wherein the gas barrier layer is adhered to the rubber layer by using an adhesive.
However, the production needs to be conducted under certain conditions in order to realize the resin-rubber adhesion at the desired level by using an adhesive or the like, and this results not only in the increased number of production steps but also in the difficulty of conducting continuous production of the hose as well as the increased production cost. Use of an adhesive or the like is also associated with the problem of the use of an organic solvent which has harmful effects on the global environment.
In view of such situation, JP 3891718 B and JP 2002-079614 A propose a hose wherein the resin layer and the rubber layer are adhered without using any adhesive.